biology review Flashcards

Question

Cholesterol

Answer 1

Stabilizes membrane what keeps structure so not over crowded or far away making it better at what what passes through it

Answer 2

Help transport material through the cell membrane especially when they have a hard time passing through

Answer 3

Act at enzymes speed up reactions attracting cytoskeleton structure to help with cell shape

Answer 4

Pressure created by water moving across the membrane due to osmosis More water moving=higher osmotic pressure

Answer 5

-distance the greater distance need to be travelled the slower diffusion rate - higher temp more movement of molecules therefore diffusion faster - particle size smaller particles faster rate of diffusion

Answer 6

Movement of water through a semipermeable membrane(high concentration to low ) Water molecules can travel through cell membrane or through protein channels in larger quantities Low water= high solute concentration(eg sugar) -water loves to move towards solute

Answer 7

-higher solute(sugar, salt) concentration, less water -lower solute concentration, more water

Answer 8

Opposite of diffusion goes against concentration gradient so low to high concentration atp is needed

Answer 9

-Outer boundary of cell -Protects the cell -Composed of lipid molecules that are interspersed with tiny protein channels. -Controls what enters and leaves the cell.

Answer 10

Hydrophilic (water-loving) — dissolve in water. These are often lipophobic. Hydrophobic (water-fearing) — dissolve in lipids (lipophilic).

Answer 11

it requires one organism to make more (children) - they are genetically identical(clones), have no genetic variety

Answer 12

-efficient and fast since it involves one organism -population could be wiped out in unfavourable environment as they are all vulnerable to the same conditions due to genetics

Answer 13

the uniting of gamete(reproductive cell) to make new organisms -genetically diverse as they are receiving from two diff. parents

Answer 14

this process only occurs in prokaryotes 1. has to grow 2.replicate all genetic material (DNA, Plasmids) 3.starts to grow new cell when complete they pull apart

Answer 15

cells can divide without order and accumulate genetic errors that can lead to a cancerous tumour

Answer 16

- DNA replicates -centrioles become visible

Answer 17

-chromatin condenses - centrioles move to poles of cell and start to project spindle fibres -nuclear membrane breakdown

Answer 18

-spindle fibres attach to chromosomes - chromosomes line up in the centre of the cell

Answer 19

- spindle fibres contract - sister chromatids pulled apart

Answer 20

- new nuclear membrane forms -chromosomes de-condense

Answer 21

to ensure that that all the chromosomes are aligned at the spindle equator before anaphase is initiated.

Answer 22

cell undergoes growth increasing amount of cytosol. it also synthesis proteins that are needed for DNA replication

Answer 23

further growth in preparation for cell division, DNA duplicated

Answer 24

the parent cell synthesises or replicated DNA by the end it has two identical copies of its original DNA

Answer 25

mitosis and cytokinesis - spindle fibres have formed and chromosomes have lined up in the right position - division of cel

Answer 26

A) self renewal ability to divide while maintaining unspecialised state B)potency ability to differentiate and transform into specialised cells

Answer 27

most powerful potency found in zygote

Answer 28

any cell expect embryonic cell found in placenta

Answer 29

rise to limited number of cells found in bone marrow

Answer 30

The two mechanisms by which apoptosis can be achieved are: an intrinsic (internal) signal within the cell. This is also known as the mitochondrial pathway. The intrinsic pathway is used when cells come under stress, such as through infection or damage. When cells are damaged during the cell cycle and the damage cannot be repaired, they undergo apoptosis via the intrinsic pathway. an extrinsic (external) signal, where the signal is from a source external to the cell. This is also known as the death receptor pathway. One way this may be generated is by a signal from the immune system.

Answer 31

breakdown of normal cells is mutated cell= uncontrollable growth

Answer 32

shoot system the above-ground system of plants, the site of photosynthesis, transport of sugars and the site of reproductive organs

Answer 33

Root system the below-ground system of plants which anchors the plant in the soil, is responsible for the absorption and conduction of water and minerals, and the storage of excess sugars (starch)

Answer 34

-no cell division -already formed specific cell/specialised

Answer 35

-always growing/dividing

Answer 36

dermal tissue: -"skin" -epidermal -green --->chlorophyll --->traps sunlight ground tissue: -roots, H2O uptake vascular tissue: transport of water and nutrients

Answer 37

stem cells; undifferentiated cells that become other cells

Answer 38

parenchyma tissue — In leaves, the parenchyma tissue is the site of photosynthesis. In roots, tubers and seeds, the parenchyma tissue is the site of storage of starch collenchyma—thick, flexible walled cells in plants; the main supporting tissue of stems sclerenchyma —dead cells with thickened walls for strength and rigidity

Answer 39

xylem: -H2O and minerals transport -includes tracheid and vessals Phloem: -nutrient transport -glucose for photosynthesis

Answer 40

Tracheids are present in all vascular plants and are long and tubular, whereas vessels are only present in flowering plants and have a wide pipe-like structure

Answer 41

Uptake of water by plants occurs through osmosis by the root hairs. Root hairs are extensions of cells of the epidermal tissue that forms the outer cellular covering of the root.

Answer 42

The stomata are the sites of carbon dioxide uptake and loss of water in a plant. Stomata are mainly located in the lower epidermis of leaves. Water is lost as vapour when a concentration gradient exists between the water content in the leaf spaces (high) and in the air outside the leaf (low) and the leaf stomata are open

Answer 43

mechanical digestion: physical breakdown of food smaller pieces done by teeth and tounge Chemical digestion (Break chemical bonds in food ): *Lubrication of food * Enzymes -(salivary amalayase ) * break down carbohydrate

Answer 44

* Moves food from the throat to the stomach → Muscle movement called peristalsis * If acid from the stomach moves back into the oesophagus=heartburn

Answer 45

*muscular organ which further churns food ,forming chyme mush(mechanical digestion)and mixes it with pepsin(enzyme that begins chemical digestion of protein)

Answer 46

*the small intestine produces intestinal juice which contains amylase(starch to breakdown) protase and lipase(digests fats to fatty acid) FUNCTION: digestion and absorption of food occurs here *nutrients from the food pass into blood stream (carbohydrates and protein) →villi and microvilli increase SA to help with absorption

Answer 47

filtration of the blood coming from from the intestine before it is passed down to the rest of the body. * Filters out toxins and waste. Detoxifies poisonous substances

Answer 48

BILE Is a fluid that is made and released by the liver and stored in the gallbladder. Bile helps w/ digestion. It breaks down fats into Fatty acids, Bile contains: Mostly cholesterol

Answer 49

- produce compounds to digest fats and proteins - regulates blood sugar by producing insulin

Answer 50

absorption of water and storage of the remainder of the waste material

Answer 51

endocrine system is a network of endocrine glands that deliver chemical messages (hormones) in the blood stream to target tissues. endocrine glands: produce hormones. → Unlike exocrine glands which produce enzymes, sweat, tears endocrine glands are ductless and secrete, their hormones direly into the bloodstream.

Answer 52

A chemical messenger (signalling molecule) which targets a group of cells in order to cause that group of cells do some activity or stop doing an activity

Answer 53

→ controls the endocrine system

Answer 54

secretes a diff. hormones: - Growth - Blood pressure - Metabolism

Answer 55

→ regulates rates of metabolism in the body

Answer 56

→ control metabolism of calcium

Answer 57

→ Hormones released are cortisone and adrenaline * function of cortisone: regulate carbohydrate, protein, and fat metabolism * function of adrenaline: raise blood sugar levels and increase heartbeat and breathing rates

Answer 58

the excretory system is responsible for removing metabolic and other wastes (excess, unnecessary or dangerous materials)from the blood and plays a role in water balance.maintaining homeostasis or internal environmental balance The Excretory system in consists of organs (skin, the liver, the lungs and the kidney) which are responsible for the elimination of metabolic wastes

Answer 59

ammonia and urea from the metabolism of protein creatine and creatinine from the metabolic activities of skeletal muscle.

Answer 60

Goal is to process waste products from the blood to create urine (functional unit of a kidney)

Answer 61

Glomerular filtration: Blood pressure forces fluid from the blood in the glomerulus into the bowman’s capsule The filtrate contains a mixture of glucose, salts, vitamins, nitrogenous wastes and other small molecules

Answer 62

Reabsorption is the process by which water and useful solutes are removed from the filtrate and returned to the blood. The major site of reabsorption is the proximal tubule When the filtrate exits the glomerulus, it flows into a duct in the nephron called the renal tubule. As it moves, the needed substances and some water are reabsorbed through the tube wall into adjacent capillaries. move by simple diffusion, facilitated diffusion or active transport(require atp) from the tubule into the surrounding capillaries. All nutrients, such as glucose and amino acids, and most of the water and inorganic ions, such as sodium, potassium, phosphate and calcium are reabsorbed across the wall of the proximal tubule and enter the peritubular capillaries of the blood stream

Answer 63

Tubular secretion: Secretion is the process of transporting specific compounds, typically waste products, out of the blood of the peritubular capillaries into the tubular filtrate that will eventually become urine. Secretion occurs mainly in the proximal tubule, but some also occurs in other regions of the tubules Secretion occurs mainly by active transport, but some also occurs by passive diffusion

Answer 64

filters small solutes from the blood

Answer 65

reabsorbs ions, water and nutrient removes toxins and adjusts filtrate pH

Answer 66

selectively secretes and absorbs different ions to maintain blood PH balance

Answer 67

A reabsorbs solutes and water from the filtrate

Answer 68

Its main function is to reabsorb water and sodium chloride from the filtrate. This conserves water for the organism, producing highly concentrated urine.

Answer 69

A negative feedback loop is a process in which the body senses a change in a variable and activates mechanisms to reverse the change. Negative feedback is a key component of homeostatic control loops that regulate many body variables and maintain the body’s internal conditions within narrow limits. a stimulus response mechanism where a change in a variable is detected (the stimulus) and a response occurs which reverses the direction of change, bringing the variable back within normal range.

Answer 70

The process by which an organism regulates the water balance in its body and maintains the homeostasis of the body is called osmoregulation. Osmoregulation is the maintenance of a constant osmotic pressure of the body fluids within a normal range Controlling water balance is important to ensure the cells of the body are in equilibrium Too much water outside cells and the cells will absorb it, possibly lysing(the breakdown of a cell caused by damage to its plasma (outer) membrane.) Too little water inside cells and the cells will release water, possibly collapsing

Answer 71

Afferent arterioles deliver blood to the glomerulus, and efferent arterioles carry blood away from the glomerulus. Afferent: approaching nephron=high oxygen, lower carbon dioxide, high urea, unbalanced ions and water Efferent: leaving nephron=lower oxygen, higher carbon dioxide, lower urea, balanced ions and water.

Answer 72

N waste Advantage Disadvantage Ammonia Less energy to produce Highly toxic requires a lot of water Urea Moderate energy required to produce Still requires water for excretion, so water loss still an issue Uric acid Very little water required, low toxicity High energy cost for production

Answer 73

Reabsorption from the proximal tubule to the blood is enhanced by the presence of microvilli on the epithelium that greatly increase the surface area available for reabsorption

Answer 74

Long proximal convoluted tubule: increases water reabsorption Found in marine fish Greater surface area for reabsorption to occur Short proximal convoluted tubule: decreases water reabsorption Found in freshwater fish Less surface area for reabsorption to occur

Answer 75

Small glomeruli & bowman’s capsule: reduces filtration rate Found in saltwater fish Less volume of filtrate Saltwater fish lose toxic ammonia over gills, the kidney is not required to filter N-waste form blood Minimise water loss in urine Large glomeruli & Bowman’s capsule increase filtration rate: maximise filtration rate Greater volume of filtrate, increase water loss in urine

Answer 76

Large loop of Henle: increases water & ion reabsorption Found in terrestrial organisms that live in dry environments and need to conserve water Increases water reabsorption Minimise water loss in urine Excrete highly concentrated urine Small loop of Henle: reduces water & ion reabsorption. Found in organisms that live in moist environments Less water reabsorption less concentrated urine excreted

Answer 77

Heavy vascularisation = large surface area for rapid reabsorption of water and solutes back into the bloodstream = more reabsorption Light vascularisation = small surface area, decrease reabsorption of water back into the bloodstream

Answer 78

The rate of transpiration is affected by environmental factors: humidity: the greater the content of water vapour in the air, the lower the rate, such that at 100 per cent humidity in the air, net water loss by transpiration stops wind speed: transpiration is least in still air and, all other things being equal, increases as wind speed increases, as moving air removes water vapour from around the leaves temperature: as temperatures increase, the rate of evaporation of water increases light intensity: light stimulates the opening of the leaf pores (stomata). humidity: the greater the content of water vapour in the air, the lower the rate, such that at 100 per cent humidity in the air, net water loss by transpiration stops wind speed: transpiration is least in still air and, all other things being equal, increases as wind speed increases, as moving air removes water vapour from around the leaves temperature: as temperatures increase, the rate of evaporation of water increases light intensity: light stimulates the opening of the leaf pores (stomata).

Answer 79

High solute low water

biology review Flashcards

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